Conduit threader



March 14, 1961 c. P. XENIS CONDUIT THREADER 4 Sheets-Sheet 1 Filed June26, 1958 22 mlll I N V EN TOR. Co/vsrmv r/NEPXEN/S.

March 14, 1961 c.' P. XENIS 2,974,932

CONDUIT THREADER Filed June 26, 1958 4 Sheets-Sheet 2 mmhwyzkwATTORNEY-i March 14, 1961 c. P. XENIS CONDUIT THREADER 4 Sheets-Sheet 3Filed June 26, 1958 March 14, 1961 c. p. XENlS 2,

' CONDUIT THREADER Filed June 26, 1958 4 Sheets-Sheet 4 R! Q Q QINVENTOR.

CONJTANTINEPX ENIJ:

Mia/MM? United I States Patent O CONDUIT THREADER Constantine P. Xenis,Douglaston, N.Y., assignor to Consolidated Edison Company of New York,Inc., New York, N .Y., a corporation of New York Filed June 26, 1958,Ser. No. 744,860

9 Claims. (Cl. 254-1345) This invention relates to apparatus fortraveling through pipes, conduits and the like, and more particularly toapparatus for threading such pipes or conduits.

This invention comprises an improvement over the apparatus shown in mycopending US. Patent application Serial No. 581,630, now Patent Number2,917,762.

In such copending patent application the invention, in one form thereof,is constituted by an apparatus for traveling through pipes and the likewhich includes in combination a pair of coaxial brush devices eachhaving bristles extending outwardly in circumferential array from acore, oppositely extending of such bristles being adapted to engageconcurrently opposite inner surfaces of the pipe while they are tiltedin a common direction with respect to the longitudinal axis of the brushdevice. Such pair of brush devices support therebetween suitablevibratory power means which can vibrate the cores of the brush devicesin directions substantially at right angles to the longitudinal axis ofthe apparatus. Such vibratory power means can comprise, for example,means for moving the cores of the brush devices so that they generate agenerally conical surface of revolution thereby to cause the apparatusto advance through the pipe. Alternatively, the vibratory power meanscan vibrate merely laterally of the longitudinal axis of the apparatus.'Where a vibratory power device is employed which causes thelongitudinal axes of the brushes to move in a path conforming to aconical surface of revolution, this form of motion results in advancinglinearly the extremity of each bristle in the conduit by causing itsouter extremity to scrape forwardly on the inner wall surface of thepipe in response to such vibratory force which angularly shifts thebrush core in such a way that the bristle is so caused to move, anoppositely extending bristle maintaining a foothold on the oppositeinner wall surface of the pipe thereby facilitating such advancement.Generally opposed pairs of bristles thus are manipulated successivelyaround the angular extent of a cylindrical brush thereby to cause theapparatus to advance itself through the pipe.

The cores from which the bristles extended in the aforementionedcopending patent application have been rigid metal devices in which thebristles are rigidly held.

The improvement embraced by the present invention comprises, in one formthereof, an apparatus such as that above described but wherein eachbrush core is constituted by a relatively thick sleeve of resilientrubber-like material supported by a central supporting member, such as ametal rod, the bristles being embedded in the sleeve. Because of suchresilient sleeve mounting for the bristles, the latter can be and arerelatively more stiflf and straight as compared to the bristles of suchcopending application thereby achieving the advantages set forth below.

The invention in still another form thereof comprises a device asdefined above with the exception that the two brush-like devices,instead of having the bristles thereof tilted in a common direction withrespect to the longitudinal axis thereof, that is, all of the bristlesof both brushes tilted backward with respect to the direction ofmovement, is constructed wherein the bristle tilt of one of the brushesis in one direction and that of the other brush is in the oppositedirection. Means are employed for selectively covering up or housing oneor the other of such brushes thereby providing an apparatus which isable to move either forward or backward within a pipe depending uponwhich of the brushes is covered. The device for covering a brush is, inthe form shown, a cylindrical sleeve preferably of hard metal whichsurrounds the apparatus and is axially movable relative thereto from oneend thereof to the other for the purpose of covering the outerextremities of either one of the two brushes. Suitable remote controlmeans are provided for axially shifting such cylindrical sleeve so thatit covers either one or the other of the brushes.

One of the objects of the present invention is to provide an apparatusof the above character having a brush construction which will permit theuse of the stiffest possible bristles in the brushes, bearing in mindthat the brush construction must not fit too tightly in a pipe.Relatively stiff bristles enable the most economical use or best use ofthe power of the vibratory motor permitting maximum speed at maximumthrust in the pipe, this being attributable to a minimizing or reducingof any bowing of the brush bristles. Excessive bowing of the brushbristles reduces the traction of the device in a pipe and causes a lossof power otherwise devoted to the production of forward thrust.

Thus, another object is to provide a construction of the above characterwhich permits the use of bristles which can tilt or change the attitudethereof as a result merely of being thrust in a pipe and without anyappreciable bowing of the bristle, such bristles also not being subjectto any appreciable bowing as a result of the actuation of the vibratorypower means which is connected thereto and which causes the advancethereof through the conduit.

A further object is to provide a device of the character describedhaving such brushes and bristles wherein there is prevented an excessivebending or bowing of the bristles when the device is pulled backwardsthrough a pipe after being allowed to crawl into the pipe, such bendingor bowing tending to cause a permanent set in the metal of the bristlesand thus preventing an eflicient crawling action of the device.

A further object is to provide an apparatus of this character havingimproved traction characteristics.

Another object is to provide an apparatus of this character havingimproved efficiency in the use of its motor power.

A further object is to provide an apparatus of this character havingimproved forward thrust and improved speed.

Another object is to provide an apparatus of this character which can bereversed when in a pipe without dam age to the apparatus. A

Various further and more specific objects, features and advantages ofthe invention will more clearly appear from the detailed descriptiongiven below taken in connection with the accompanying drawings whichform a part of the specification and illustrate, by way of example,

preferred forms of the invention which consists in such novelcombinations of features as are shown and described herein.

In the drawings:

Fig. 1 is a side elevation, partly in section and with parts brokenaway, showing one form of apparatus embodying the invention;

Fig. 2 is a view, partly in section and with parts broken away, of theforward extremity of an apparatus embodying the present inventionshowing the details of a front brush device and the construction of itscore;

Patented Mar. 14, 1961 Fig. 3 is a sectional view, with parts brokenaway, taken substantially along line 3-3 of Fig. 2;

Fig. 4 is a side elevation of a dished plate-like or disclike spacerelement of resilient rubber-like material which is employed as a part ofa core of a brush device as shown in Fig. 2;

- Fig. 5 is an end view of the element shown in Fig. 4;

Fig. 6 is a side elevation of a pair of brush bristles or tines whichare joined in hairpin or U-shaped form and which are employed in theform of the invention shown in Figs. 1 and 2;

7 Fig. 7 is a side elevation, partly in section and with parts brokenaway, of a brush device embodying another form of the present invention;

Fig. 8 is a fragmentary view of a portion of Fig. 7 but on an enlargedscale showing a modified form of brush bristle;

Fig. 9 is a fragmentary view of a further modification of a brushbristle;

Fig. 10 is a side elevation, partly in section and with parts brokenaway, of still another form of brush device employed in the presentinvention;

Fig. 11 is a sectional view taken substantially on line 11-11 of Fig.10;

Fig. 12 is a perspective view of a sleeve-like core of resilient rubberor rubber-like material which is employed in the form of the brushdevice of Fig. 10;

Fig. 13 is a perspective view of a portion of a brush core which isemployed in the brush device of Fig. 10;

Fig. 14 is a side elevation, partly in section and with parts brokenaway, of still another form of the invention comprising a reversibleapparatus for threading conduits or traveling through pipes, and showingsuch apparatus located within a pipe and adapted for traveling in onedirection, namely, to the left, as viewed in this figure;

Fig. 15 is a sectional view taken substantially on line 1515 of Fig. 14;

Fig. 16 is a fragmentary view on a somewhat enlarged scale of amodification of a brush device which may be employed in the embodimentof Fig. 14; and

Fig. 17 is a fragmentary view of a portion of the brush device of Fig.16 but in a different operating position.

Referring to the drawings in greater detail, with particular referenceto Fig. l, the apparatus shown therein is generally designated 20 and isconstituted by a motor 21, to the front and rear extremities of whichrespectively are connected or secured coaxial brushes 22 and 23, suchbrushes being, in the form shown, of cylindrical configura'tion havingrespectively cores 24 and 25 from which protrude outwardly incircumferential array a plurality of bristles, namely, bristles 26 forthe forward brush 22, and bristles 27 for the rear brush 23. The cores24 and 25 of such front and rear brushes each include a rubber orrubber-like layer or sleeve in which are embedded the bristles or tinesof the brushes. Such layer or sleeve is designated 28 for the brush 22,and 29 for the brush 23. The sleeves 28 and 29 are supported bycentrally extending rigid metal rods 30 and 31, respectively.

The motor 21 is provided with an armature 32 having a shaft 33 whichextends longitudinally of the apparatus and coaxially with the brushes22 and 23. That is, the longitudinal axes of said brushes 22 and 23 andof the motor 21 are in coincidence.

The apparatus of Fig. 1 is caused to advance in a conduit 34, in which.it is inserted, by suitable vibratory means which causes the apparatusto shake or quiver laterally of the longitudinal axis of the apparatusin the manner described in said copending patent application. As shownin Fig. 1 herein, the armature shaft 33 is pro- I vided at oppositeextremities thereof with eccentric weights 35 and 36 respectivelypositioned upon the front and rear extremities thereof which aresituated 180 out of phase and which in response to rotation of thearmature cause the longitudinal axis of the apparatus to genconduit.

erate a cone, that is, to move in a path conforming to a conical surfaceof revolution.

In order to permit the use of times or bristles (26, 27) which are asstiff as possible without disadvantageous frictional effects, theaforementioned rubber sleeves 28, 29 are employed. The details of theconstruction of core 24 are shown in Fig. 2. The employment of therubber mounting for the bases of the bristles, as in the core 24,permits a change in the angle of each bristle when it is thrust into apipe thereby to accommodate the smaller inner diameter of the pipe andthis Without any appreciable bowing of each bristle by virtue of itsrelatively stiff nature. Such appreciable or relatively greater bristlebowing militates against the efiicient operation of the apparatus, asaforementioned, by absorbing disadvantageously some of the vibratorypower of the apparatus, and causing such vibratory power (e.g. vibratoryin generating a conical surface of revolution) to be wasted inincreasing the extent of the initial bowing of the bristles rather thanin pushing the apparatus through a pipe.

in the form shown in Fig. 2, the brush 24 comprises a plurality ofdished plate-like or disc-like spacer elements 37, there being eight insuch figure, which elements are consecutively and coaxially mounted, andclamped by suitable end plates 38 and 39 with the aid of theaforementioned rigid central rod 30 which urges such end platestogether. Each ofthe dished plate-like elements 37 is of resilientrubber-like material and, with the exception of the one at theright-hand extremity designated 37', is provided with a plurality ofU-shaped grooves 40 well illustrated in Fig. 5, which grooves aredesigned for receiving the inner U-shaped portions of a pair of joinedbristles or tines 41 (Figs. 3 and 6).

A plurality of such bristle pairs '41 are thus placed in the grooves 4sprior to pressing the dished plate-like elements 37 together coaxiallyand such bristles are held in position by clamping such elements 37together, as shown in Fig. 2. Preferably a suitable adhesive is appliedto the adjacent faces of the elements 37 in order to ensure a firm andsecure bond between such elements which will prevent the dislodging ofthe bristles 41 in their grooves 40.

As shown in Fig. 2, forward brush 24 is secured to the front end ofmotor 21 by means of a plurality of angularly spaced parallel bolts 42,the position of the uppermost one of which is well illustrated in Fig.3, it passing between the vertical arms of a bristle pair 41. The bolts42 threadedly engage the motor 21 in the manner shown in Fig. 2 andpreferably extend parallel to the longitudinal axis of the apparatus 20.

Reverting to Figs. 3 and 6, it will-be seen that inner extremity 41a ofbristle pair 41, when positioned in a groove 49, is spaced from thecentral rod 30. However, if desired, the grooves 40 for receiving thebristles 41 may be so disposed in each of the spacer elements 37 thatsuch inner bristle extremity 41a is in contact with the rod 30.

Referring to Fig. 1, the motor 21 is energized by electrical powerreceived via an electrical power line 43 which is connected to asuitable source of electrical power (not shown). The power line 43, asis shown in Fig. 1, may be directed to the motor 21 via a passage in acentral rod 31 which protrudes rearwardly from the apparatus 20 as shownin such figure. At the aftermost extremity of the rod 31 a suitable eye44 may be formed which preferably is connected to a cable or cord 45designed for the purpose of pulling the device 29 backwards out of apipe or conduit when this becomes necessary.

Referring now to the degree of tilt of the bristles, I have found itadvantageous to construct and arrange such bristles whereby the angle oftilt is about 12 to 15 prior to the insertion of the apparatus into aconduit, such tilt increasing to about 25 to 40 when inserted in theSuch angle of tilt is, of course, measured at Thus the angle of tilt ofthe bristles shown in such- Fig. 2 prior to insertion of the brush intoa conduit is of the order of 15 and, as shown in Fig. 1, such angle oftilt is of the order of 25".

I have found that this provides suitable traction for the apparatus andby selecting the stifiness of the bristles and the hardness orresilience of the sleeves 28 and 29, a minimum amount of friction iscreated which will tend to retard the advance of the apparatus and atthe same time the degree of bowing of the bristles is also minimized inorder to achieve the advantages above set forth with respect to mostefi'icient use of the propelling power of the motor 21.

A second embodiment of the invention comprises one identical to thatshown in Fig. 1 with the exception that a modified form of brushconstruction is employed which is illustrated in Figs. 7, 8 and 9.

Such modified form of brush construction is illustrated with respect toa front or forward brush 46 (Fig. 7) which is constituted by a solidsleeve 47 of rubber or rubberlike material of selected resilientqualities, for example, of a rubber hardness of 60-70 Durometer-Shore-A.A similar rubber hardness may be employed with respect to all of theresilient or rubber-like mountings for the bristles described herein.

The resilient sleeve 47 is supported by a rigid central rod 48 which, atits righthand extremity, is secured to the forward end of the motor 21.

The central rod 48 thus provides a rigid support for the sleeve 47 andfor the forward brush member, there being embedded in the sleeve 47 aplurality of bristles 49, the inner extremity of one of which isillustrated in Fig. 8. Such bristles 49 (Fig. 8) may be of suitablegauge spring steel such as piano wire having formed at the inner endthereof a barbed hook 50 which resembles somewhat the end of a fishhook.The bristle 49 is installed in the sleeve 47 by thrusting same, at adesired angle, into the sleeve until the pointed extremity engages therod 48. If desired, a suitable pilot recess or passageway can bepreformed in the sleeve 47 to receive each of the bristles 49.

In lieu of the bristle 49 of Fig. 8, bristle 51 can be employed having aplurality of barbs, such as 51a (Fig. 9), formed along the inner partthereof adapted to be buried in the resilient sleeve 47.

As is shown in Fig. 7, the brush construction 46 also embraces endplates 52 and 53 respectively on the forward and rear extremities, suchend plates, if desired, exerting a suitable squeezing pressure upon theresilient sleeve 47. Furthermore, if desired, the brush construction .46may be, as is shown in Fig. 7, attached to the forward end of the motor21 as by bolts 53a which extend parallel to the longitudinal axis of therod 48.

Another embodiment of the invention may be employed which also isidentical to that of Fig. l with the exception of a modification of thebrush construction as shown in Figs. l0l3, inclusive. In Fig. themodified form of brush construction is generally designated 54 andcomprises a sleeve 55 also of resilient rubber-like material, whichsleeve extends substantially the full length of the brush constructionas in the embodiment of Fig. 7 and in which are embedded a plurality oftines or bristles 56. The bristles 56 distinguish from the bristles 49of the embodiment of Fig. 7 by virtue of a difierent construction oftheir inner extremities which, in lieu of a'sharp barb 50, employ acurved hook conformation as at 57 which has a rounded end, for example,formed on 3. ,6 inch radius.

The resilient sleeve 55 preferably is provided with a plurality of pilotholes or passageways in which may be inserted the hooked or innerextremity of each brush bristle, the bristle being inserted with thehook first and thrust inwardly (the metal core of the rubber sleevebeing removed) until the hook is fully through the rubber or rubber-likewall of sleeve 55 and then the hook is retracted to the position asshown in Fig. 10.

By way of example, overall dimensions of one size of the brushconstruction of Fig. 10 are as follows:

Inches Outer diameter 4%; Overall length, that is, from the extremity ofone end plate to the other 3%;

in Fig. 13, this constituting, for example, the forward one, a similarone being employed in the rear extremity. Such forward element isdesignated 58 and the rear one 59. The forward element 58 includes aforward end plate 60 with which is integrally formed a stud or post 61which, in the form shown, in length is one-half the length of the brushconstruction 54. The element 59 is of analogous construction having anend plate 62 and a central stud or post 63, the inner extremity of whichabuts at 64 with the inner extremity of the stud or post 61. The lengthsof the studs or posts 61 and 63 are selected for the purpose of giving adesired compressing effect upon the rubber or rubber-like sleeve 55 inwhich are embedded the bristles 56.

The brush construction 54 is held in an assembled condition preferablyby longitudinally extending bolts 65 (Fig. 10) which are, in the formshown, four in number and are spaced angularly by and located near theperiphery of the brush construction and which extend into threadedengagement with the front extremity of the body of the motor 21, as iswell shown in Fig. 10. Suitable grooves 66 are formed at 90 intervalsabout the periphery of the sleeve 55 for the purpose of accommodatingthe longitudinally extending threaded bolts 65.

Referring now to the form of the invention shown in Figs. 14-17,inclusive, there will now be described an embodiment which can beidentical to any of the previous embodiments of the invention with theexception that there are in addition provided a relative disposition ofthe forward and rear brushes and suitable means so that the device isreversible. That is, the angle of tilt of the bristles of the forwardbrush is opposite to that of the rear brush, and means are provided forcovering up selectively one or the other of such brushes as by anaxially shiftable cylinder which will permit the uncovered brush tothrust the apparatus in a desired direction, it being understood thatthe direction of thrust can be reversed by axially shifting the coveringdevice into an opposite position.

Such a reversible form of the duct rodding device, that is, reversibleby its own action, is designated generally at 67 (Fig. 14) and isconstituted by a motor 68 which preferably is identical with the motor21 of Fig. l, and to which motor are secured at the opposite extremitiesthereof a pair of coaxial brushes 69 and 70, the bristles 71 and 72thereof, respectively, being tilted in opposite directions instead of ina common direction.

For purposes of obtaining a reversal of motion of the apparatus of Fig.14, there is connected thereto in a manner to be more fully set forthbelow an axially shiftable cylinder or housing 73 which is of a selectedlength and which is mounted upon the motor 68 in such a way that it canbe shifted axially to a lefthand extreme as shown in solid lines in Fig.14 wherein it covers the extremities of the bristles 71 therebyimmobilizing same insofar as their driving force is concerned, andpermitting the righthand brush construction 70 to become the onlyoperable or propulsive brush construction and which, under the influenceof the motor 68, will advance the brush to the left, as viewed in Fig.14.

For the purpose of facilitating the operation of this device, a pair ofspider supports 74 and 75 are provided, the latter being illustrated inFig. 15. Each spider support is capable of supporting its respectiveextremity of the apparatus in a centered position within a conduit 76but not concurrently. That is, one or the other is always immobilized.

The function of the spider supports is to ensure that that extremity ofthe apparatus where the brush is immobilized is held in a centralposition in a conduit, the spider at the opposite end being immobilizedand relying upon the adjacent brush construction for the purpose ofholding such opposite end in a substantially centered position Thus inthe form shown, the spider support 75 consists of four radiallyextending legs 77 spaced apart by 90 and each being spring mounted forradial extension or contraction under the influence of coil springs 73(Fig. 14). Thus each leg 77 is constituted by two portions, namely, aportion 78 upon which is rotatably mounted a wheel 80, the portion 79being rod-like in conformation and telescopically engaging a tubularportion 81 in the central passage of which is located the aforementionedspring 78 which urges outwardly the portion 79.

The cover or cylindrical housing 73 is provided with suitably conformedopenings, such as 73a and 73b, which are of adequate longitudinal extentand suitably positioned peripherally of the housing to ensure that thespider support (e.g. 74) adjacent the housed or covered brush isoperative and that the legs thereof extend through their respectiveopenings 73a to permit the respective rollers or wheels St} to engagethe inner surface of the conduit 76. And conversely that the otherspider support (eg. 75), adjacent the brush which is operative to propelthe apparatus, is rendered temporarily inoperative by virtue of itsouter Wheels riding upon the interior surface of the housing as is wellshown in Fig. 14.

The manner of operatively interconnecting the cylindrical housing 73 tothe motor 68 to permit the aforementioned axial relative motion is alsoshown in Fig. 14 and comprises a series of axially extending rods, suchas 82, which are spaced about the periphery of the motor 68 and whichare secured thereto as by arms 83 and 84. Such rods in turn pass throughpassages 850 formed each in an arm 85, the latter being rigidly securedto the inner surface of the cylindrical housing 73 and extendingradially inwardly thereof.

The coaction of the rods 82 and the radially inwardly extending arms 85thus permits axial movement of the cylindrical housing 73 between thelimits shown in Fig. 14, that is, between the position of the housingshown at its leftlland extremity in solid lines and the position thereofas shown at its righhand extremity in broken lines.

Any suitable power means can be employed for so axially shifting thecylindrical housing 73 between its extremes of motion in orderselectively to activate one of the brushes and deactivate the other.Such means, in the form shown in Fig. 14, comprise a relatively smallmotor 86 mounted upon the lefthand upper extremity of the larger motor68 (Fig. 14) to which its drivably connected a threaded rod 87 whichengages a threaded recess 88 of an arm 89, the latter being secured tothe inner extremity of the cylindrical housing 73. Thus the latterhousing 73 can be axially shifted by rotating the rod 87 by the motor86.

Suitable control means for the motor 86 may be provided. Electricalenergy for the motor 86 is directed thereto by an electrical cord 90which, in the form shown, extends through the brush 70, together withanother electrical lead or cord 91, the latter being for conductingelectrical energy to the motor 68. Both of the cords and 91 emerge fromthe righthand extremity of the brush 70 and are bound together to form ajoint electrical cord 92 which is connected to suitable sources ofelectrical energy and control means.

Limit switches 93 and 94 mounted on motor 68 are provided for stoppingthe motor 86 in response to the cylindrical housing reaching itslefthand or righthand extremity, as viewed in Fig. 14. That is, theswitch 93 is positioned for coacting with the radially inwardlyextending arm 89 in the manner shown, and when the latter is in itslefthand extremity such switch is actuated to stop the motor 86.Conversely, the switch 94 is positioned for stopping the motor 86 whenthe housing 73 has moved to its righthand extremity and the arm 89 is inthe position shown in broken lines in Fig. 14.

Inner surface 730 of the housing 73, which surface is positioned forengaging the outer extremities of the bristles 71, is preferably formedwith a hard and polished surface, for example, a chromium plated surfacewhich is of a degree of hardness to prevent the extremities of thebristle 71 from gaining a foothold thereupon and thereby retarding orhindering the disengagement of such inner surface 73c when it is desiredto shift axially the housing 73 to its righthand extremity from thatshown in Fig. 14. Analogously the inner surface 73d of the housing 73 isformed with a hard highly polished surface and for a similar purpose.

In order to facilitate the engagement and disengagement of the innersurface of the housing 73 with the ends of the brush bristles of bothright and left brushes, the outer end portions of the bristles may beformed as shown in Figs. 16 and 17. That is, bristles 71a (e.g. of theleft brush) may be employed which are identical to the bristles 71 withthe exception that the outer portions 71b thereof are bowed or bent in acommon direction in the manner shown in Fig. 16. The extent of thebowing or bending is not enough to reduce appreciably the traction ofthe device. However, the extent of such bowing is enough to facilitatethe movement of the bristle extremities over the surface 730 and out ofthe cylindrical housing 73. That is, once the bristles 71a are housed bythe cylindrical housing 73, as shown in Fig. 17, the latter being ofconsiderably less inner diameter than the inner diameter of the conduit76, there is a tendency for the bristles to gain a foothold or dig intothe inner surface 73c and this tendency is minimized by the bowing ofthe outer portions of the bristles aforementioned, namely, at 71b.

Analogous bowing in the opposite direction of the outer extremities ofthe bristles of the opposite brush, of course, can be employed ifdesired.

Reverting to Figs. 1 and 2, there is no bowing of the bristles 26 in theform shown in the brush construction in Fig. 2 because the brush is notinserted within a conduit. However, in Fig. 1, which represents theapparatus inserted in a conduit, there is an enhancement of the tilt ofthe bristles as compared to Fig. 2 and a slight but almost imperceptiblebowing, the extent of the bowing being reduced to a minimum by virtue ofthe rubber or rubber-like mounting for the bristles.

In the construction of a brush device in accordance with the presentinvention, it is desirable, in order that it works at optimumefficiency, to employ relatively stiff bristles, as aforementioned,which should be able to deflect or tilt to accommodate easily the fullrange of conduit diameters for which designed, the outer dimension ofthe brush before insertion, of course, being somewhat larger than theinner dimension of the conduit.

When the brush is inserted in a conduit, the bristles deflect, that is,they undergo some bowing and also some angular shifting. It is desirableto be able so to shift the bristles angularly With the least possiblebowing, for reasons aforementioned, and this can be accomplished bymeans of the resilient rubber or rubber-like bristle mounting meansdescribed herein which permits the most economical utilization of thepower ofthe motor. Thus in the present invention it is possible toachieve a bristle deflection as a result of insertion into the conduitand with a minimum amount of bowing. It is, of course, substantiallyimpossible to employ a bristle of the length and diameter herein neededwithout some small degree of bowing but such is reduced to a minimum bythe construction embodying the invention.

Thus the bristles employed herein tilt by moving angularly relative tothe rubber core in which they are embedded and with a relatively lowdegree of bending or bowing whereby, in response to insertion of theapparatus into a pipe, the bristles are as straight as can be attainedunder the circumstances thereby preventing wasting of the propulsivepower of the vibratory motor in causing further bowing of the bristles.The vibratory power of such motor thus can be devoted to the advancingof the apparatus by causing a pushing by the outer extremities or feetof the bristles and without devoting such power to bending or bowing ofthe bristles.

Consider, for example, a construction embodying the present inventionwherein the outer diameter of the brushes prior to insertion into aconduit is 12 /2 inches. It is to be expected that the range of innerdiameters of conduits in which such a device can be employed is about 2inches, that is, say 12 inches down to inches in inner diameter. It isdesirable to attain a bristle tilt in response to insertion into theconduit which is sufiicient to permit one to push the apparatus into anysize of duct within the selected range, such as that aforementioned, andyet have the bristles remain relatively stifi and straight. By suchconstruction it is possible to accomplish the objectives of the presentinvention. That is, by means of the present invention one may make useof very stiti bristles which will permit tilt by virtue of the resilientbristle mounting but with little or no bowing of the bristles, that is,without appreciable bowing.

The outer diameter of a brush constructed in accordance with the presentinvention may be 4%; inches to be inserted into a conduit having a 4inch inner diameter. A typical example of the thickness of a bristleembodying the present invention is 32 mils to 39 mils, the materialbeing piano wire.

The bowing of the bristles has been used as the means for reducing thebrush diameter so that the brush can fit into a pipe of smaller diameterbut this is at a cost of the forward thrust of the apparatus and resultsin wasting part of the power of the propulsive means. Thus, much of thepower can be so wasted in the bowing of the bristles instead of inpushing the device through the conduit. There are two sources of waste,namely, loss of physical push or forward thrust due to bowing and alsosuch loss due to friction between the bristles and the duct, forexample, when the brushes are too tight in the conduit. The abovedisadvantage can be overcome and the best results obtained if thebristles can assume the right angle relative to the inner wall surfacesof the conduit, for example, 25 and still be relatively straight, thatis, with no appreciable bowing. This advantage is obtained by theconstruction of the present invention. However, it is to be noted thateven when the stiffest of bristles is employed, there is some degree ofbowing because it is not possible to employ a bristle construction whichis not subject to at least some small degree of bowing when the deviceis thrust into a conduit of smaller diameter than the normal outerdiameter of the brush.

Thus, by means of the present invention, there is provided a ductcrawler or duct threading device which permits the use of the stifiestpossible bristles, the characteristics of which can be selected suchthat the device does not fit too tightly in a conduit and the device, byvirtue of the brush construction, will nevertheless make the mosteconomical use of the power of the motor by gaining a maximum forwardthrust at a maximum speed of advance in the pipe due to the minimizingof such bowing.

Referring to the embodiment of Fig. 2, it is desirable to clamp tightlytogether the conical plate-like discs with the bristles locatedtherebetween because it is possible to obtain the benefit of tilt due tocompressibility of the resilient rubber-like discs and with minimumdegree of bowing. Furthermore, the cushion effect of the rubberlikematerial prevents excessive localized cold working of the bristles atany point along the length thereof which will tend to cause fracture.

One of the important advantages obtained by the construction of thedevice herein described is the elimination of the tendency of the deviceto rotate when it strikes an obstruction in a pipe. Furthermore, bymeans of the embodiment of Fig. 14, it is possible to reverse thedirection of movement of the apparatus without any damage to itsbrushes.

By means of the construction shown and described herein it is possibleto employ more stifi' Wire or bristle substance of larger diameter ascompared to that shown in the above-identified copending patentapplication.

What is claimed is:

1. Apparatus for traveling through pipes and the like comprising: abrush device constituted by an elongated core and a plurality ofbristles extending outwardly therefrom in circumferential array andbeing tilted relatively to the longitudinal axis of such core wheninserted into a pipe, said core including a layer of resilientrubber-like material supported by a rigid central support, said bristlesbeing embedded in said layer; and means for causing said device toquiver laterally of its longitudinal axis to advance the apparatus inthe pipe, said bristles being of metal and being of dimensions and ofmetal characteristics selected to make same stifi to such an extent thattogether with the selected resilience of said rubber-like material thereis substantially imperceptible bowing of the bristles when so insertedin a pipe the inner diameter of which bears relation of the outerdiameter of said brush device as defined hereinafter, the outer diameterof said brush device being of the order of about 4% to 25% larger thanthe inner diameter of such pipe in which it is to operate, and thebristle tilt relative to a plane normal to the longitudinal axis of theapparatus being not greater than about 25 to 40 when inserted in such apipe.

2. In apparatus for traveling through pipes, a pair of brushes, eachhaving a plurality of stiff bristles extending outwardly from a centralelongated core in circumferential array adequate in number to supportsaid core spaced from the inner walls of a pipe and being tiltedrelatively to the longitudinal axis of such core when inserted into thepipe, a motor, said brushes being coaxially mounted on opposite portionsof such motor, means drivably connected to said motor for shaking saidbrushes in a direction transverse to the common axis thereof, said corebeing of a resilient rubber-like material and said bristles beingembedded therein, said bristles being of metal, the resilience of therubber-like material, the metal characteristics and the dimensions ofthe bristles all being selected to cause the rubberlike material to besufiiciently yielding and to make the bristles sufiiciently stiffwhereby there is substantially imperceptible bowing of the bristles inresponse to the insertion of the apparatus into a pipe, theaforementioned tilted attitude of the bristles being not greater than ofthe order of 25 to 40.

3. In apparatus for traveling through pipes and the like, an elongatedbrush constituted by a core having a plurality of relatively stifibristles extending angularly outwardly from the core in circumferentialarray adequate in number to support the core spaced from the innersurfaces of a pipe, such core comprising a rigid central rod surroundedby a sleeve of resilient rubberlike material in which are embedded theinner extremities of said bristles, and means connected to such brushfor shaking same laterally of the longitudinal axis thereof to cause theapparatus to advance in a pipe,- said bristles being normally straightand having an angle of pretilt prior to the insertion thereof into apipe of the order of 12 to 15, the outer diameter of said brush devicebeing of the order of about 4% to 25% larger than the inner diameter ofthe pipe in which it is to operate, and the bristle tilt relative to aplane normal to the axis of the apparatus not greater than about 25 to40 when inserted insuch a pipe, said bristles being of dimensions andmetal characteristics selected to make same of a stiffness whereby,together with the selected resilience of said rubber-like material,there is substantially imperceptible bristle bowing when inserted insuch pipe.

4. Apparatus for traveling through a tube having a passage therein ofsubstantially uniform cross-sectional dimensions and comprising incombination a pair of coaxial brush-like devices, each having a coremember and a plurality of relatively stiff bristles extending outwardlytherefrom in a plurality of directions for supporting such core memberspaced from opposite sides of such passage, said bristles being adaptedto assume 7 tilted attitudes in a generally common direction relative tothe longitudinal axes of such core membersin response to insertion ofsaid brush-like devices into such passage, and a motor connected to saidcore members and supportable in between the same when in a passage, andmeans drivably connected to said motor for rapidly moving portions ofsuch core members from one side to another of a norm axis extending inthe same direction as the axis of such passage thereby to advance theapparatus in the passage, and characterized in that each of such coremembers includes a layer of resilient rubher-like material in which areembedded said bristles, the outer diameter of said brush-like devicesbeing of the order of about 4% to 25% larger than the diameter of'suchpassage, and the resilience of said rubher being selected and saidbristles being of dimensions and metal characteristics selected to makesaid bristles of a stiffness such that there is no bowing orsubstantially imperceptible bowing thereof when inserted in such pipe.

5. Apparatus for traveling through a tube having a passage therein ofsubstantially uniform cross-sectional dimensions and comprising incombination a pair of coaxial brush devices, eacn having a core memberand a plurality of relatively stiff bristles extending outwardlytherefrom in a plurality of directions for supporting such core memberspaced from opposite sides of such passage, the bristles of one of suchbrush devices being tilted in an opposite direction relatively to thebristles of the other brush device, a motor connected to said coremembers and supportable in between same when in such a passage, meansdrivably connected to said motor for rapidly moving portions of suchcore members from one side to another of a norm axis extending in thesame direction as the axis of such passage thereby to advance theapparatus in the passage, said apparatus being characterized in thateach of such core members includes a layer of resilient rubber-likematerial in which are embedded said bristles, and a sleeve-like deviceembracing a portion of such apparatus and mounted for axial movementrelative thereto for selectively immobilizing one or the other of suchbrush devices by surrounding same.

6. Apparatus for traveling through pipes and the like having a passagetherein of substantially uniform crosssectional dimensions and includingin combination, a brush device having a core to which are secured aplurality of relatively stiff bristles which are tiltable in a commondirection in response to insertion of the apparatus into such pipe, saidbristles extending outwardly from and disposed for supporting said coreinsuch pipe spaced from and thus between opposite inner surfaces of thepipe, the transverse dimension of said brush device being selected toeffect engagement of such opposite inner surfaces of the pipesimultaneously by such bristles, a; motor connected with and supportedby said brush device, and means drivably connected to said motor forvibrating said brush device laterally of the longitudinal axis thereofthereby to advance the appa'rat'us through the pipe, said brush devicebeing characterized in that the core thereof includes resilientrubber-like means in which the bases of said bristles are embedded, theresilience of such rubber-like means, and the stiffness of such bristlesbeing selected whereby said bristles undergo no bowing or substantiallyimperceptible bowing in response to insertion of the apparatus into apipe, such bristles being of metal and being of metal characteristics ofspring steel, such transverse dimension of such brush device being ofthe order of about 4% to larger than the inner transverse dimension ofthe pipe in which it is to operate. 1

7. Apparatus for traveling through pipes and the like having a passagetherein of substantially uniform crosssectional dimensions and includingin combination, a pair of coaxial brush devices each having a core towhich are secured a plurality of relatively stiff bristles, the bristlesof one core being tilted in a direction opposite to those of the othercore, said bristles extending outwardly from and disposed for supportingsaid cores in such pipe spaced from and thus between opposite innersurfaces of thepipe, the transverse dimension of said brush devicesbeing selected to efiect engagement of such opposite inner surfaces ofthe pipe simultaneously by such bristles, a motor connected with andsupported by said brush devices, and means drivably connected to saidmotor for vibrating said brush devices laterally of the longitudinalaxis thereof thereby to advance the apparatus through the pipe, and asleeve-liketdevice embracing a portion of such apparatus, and means formounting such sleeve-like device for axial movement relative to suchcoaxial brush devices for selectively immobilizing one or the other ofsuch brush devices by I surrounding the outer extremities of thebristles thereof.

8. In apparatus for traveling through pipes and the like, thecombination of: a pair of bru'shlike devices each having a core memberand relatively stiff fingers secured to the core member, such fingersbeing adapted to assume in contact with the inner surface of such pipesa tilted attitude in a generally common direction relative to thelongitudinal axis of such core members, such longitudinal axisextending'substantially in the proposed direction of motion of suchapparatus, such fingers be ing secured to such core member and extendingoutwardly therefrom in circumferential array for supporting the coremember in a pipe spaced from the inner wall surfaces of the pipe; andmeans operatively connected to said core member for vibrating such coremember to generate a substantially conical surface of revolution therebyto advance the apparatus through a pipe, characterized in that each coremember includes resilient rubber-like means for mounting said fingers,said fingers being of metal, the resilience of the rubber-like means andthe metal characteristics and dimensions of the tingers all beingselected to cause the rubber-like means to be sufiiciently yielding andto make the fingers sufficiently stiff whereby there is substantiallyimperceptible bowing of the fingers in response to the insertion of theapparatus into a pipe, the aforementioned tilted attitude of the fingersbeing of the order of 25 to 46.

9. In apparatus for traveling through a tube having a passage therein ofsubstantially uniform cross-sectional dimensions, a' pair of brusheseach having a core including resilient sleeve means supported by a rigidcenter rod and a plurality of relatively stiff bristles embedded in saidsleeve means and extending outwardly therefrom in at least two oppositedirections for supporting such cores spaced from opposite sides of suchpassage, said bristles being adapted to assume, substantially free ofbowing, tilted attitudes in a generally common direction relative to thelongitudinal axis of such cores when said brushes are inserted into suchpassage; and means in connection with said brushes and supported betweenand by such brushes for rapidly moving portions of such core membersfrom one side to another of a norm axis thereby to advance the apparatusin the passage, said bristles being of metal, the resilience of saidsleeve means and the metal characteristics and dimensions of saidbristles all being selected to cause the sleeve means to be sufficientlyyielding and to make the bristles sufliciently stiff whereby saidbristles as aforementioned are substantially free of bowing when saidbrushes are so inserted into such passage; the aforementioned tiltedattitudes of the bristles being not greater than of the order of 25 to40 relative to a plane normal to the axis of the brushes, the innerextremities of said bristles being spaced from the aforementioned rigidcenter rod while so embedded in said sleeve means thereby to enable eachbristle to react against the tube and be pushed inwardly against theresilient material of the sleeve means in response to a reverse thrustacting on the apparatus of sufiicient magnitude to reverse its movementand thus produce a reverse tilt of said bristles, thereby ing bowing ofthe bristles when the apparatus is reversed in motion through thepassage.

References Cited in the file of this patent UNITED STATES PATENTS116,823 Farley July 11, 1871 1,142,513 Churchill Sept. 12, 19392,654,433 Piety Oct. 6, 1953 FOREIGN PATENTS 614,592 Great Britain Dec.17, 1948 775,106 Great Britain May 22, 1957 799,733 Great Britain Aug.13, 1958 1,142,513 France Apr. 1, 1957

